Changes in Forced Expiratory Volume in 1 Second over Time in COPD

TLDR

COPD is characterized by an accelerated decline in FEV1, yet variability and determinants of this change in established disease are poorly understood. We followed 2163 COPD patients over 3 years, measuring FEV1 after bronchodilator use and applying a random‑coefficient model to assess predictors of baseline levels and longitudinal change. The mean annual decline was 33 ml (±2 ml), with a 59 ml/year standard deviation; 38 % declined >40 ml/year, 31 % 21–40 ml/year, 23 % changed ±20 ml/year, and 8 % improved >20 ml/year, and declines were 21 ml/year faster in smokers, 13 ml/year faster in emphysema, and 17 ml/year faster in those with bronchodilator reversibility. Funded by GlaxoSmithKline; ECLIPSE ClinicalTrials.gov NCT00292552; © 2011 Massachusetts Medical Society.

Abstract

BACKGROUND: A key feature of chronic obstructive pulmonary disease (COPD) is an accelerated rate of decline in forced expiratory volume in 1 second (FEV1), but data on the variability and determinants of this change in patients who have established disease are scarce. METHODS: We analyzed the changes in FEV1 after administration of a bronchodilator over a 3-year period in 2163 patients. A random-coefficient model was used to evaluate possible predictors of both FEV1 levels and their changes over time. RESULTS: The mean (±SE) rate of change in FEV1 was a decline of 33±2 ml per year, with significant variation among the patients studied. The between-patient standard deviation for the rate of decline was 59 ml per year. Over the 3-year study period, 38% of patients had an estimated decline in FEV1 of more than 40 ml per year, 31% had a decline of 21 to 40 ml per year, 23% had a change in FEV1 that ranged from a decrease of 20 ml per year to an increase of 20 ml per year, and 8% had an increase of more than 20 ml per year. The mean rate of decline in FEV 1 was 21±4 ml per year greater in current smokers than in current nonsmokers, 13±4 ml per year greater in patients with emphysema than in those without emphysema, and 17±4 ml per year greater in patients with bronchodilator reversibility than in those without reversibility. CONCLUSIONS: The rate of change in FEV1 among patients with COPD is highly variable, with increased rates of decline among current smokers, patients with bronchodilator reversibility, and patients with emphysema. (Funded by GlaxoSmithKline; ECLIPSE ClinicalTrials.gov number, NCT00292552.) Copyright © 2011 Massachusetts Medical Society.